There are numerous prior art uses for solid products which absorb undesirable liquids and deodorize same. An important market for such a product is animal litter, particularly cat litter. Typically, animal litter is comprised of an absorbent substrate, which can be combined with synthetic or natural deodorizing or odor-masking compounds. Absorbent substrates include alfalfa, sand, bark, clay, diatomaceous earth, peat moss, straw, vermiculite, perlite, wood particles, and various particularized wood materials such as ground hulls, ground husks, ground corn cobs, lignocellulose and the like. Deodorizing or odor-masking compounds can range anywhere from ground chlorophyl-containing plants or synthetic scents to compounds such as zeolite or fly ash. The most desirable of the above described absorbent substrates are, however, those materials which normally are considered to be waste disposal problems. Use of these materials provides not only a new article of commerce having significant commercial value but also alleviates the disposal problem itself.
One such material which is normally a disposal problem in the pulp and paper industry is the solid waste material from paper mill treatment effluent. In one process, U.S. Pat. No. 3,980,050 to Neubauer, solid waste effluent is combined with pine bark for use in a rural environment, i.e. poultry house operations under floor wire screening, where contact resistance, odor adsorbency, and dimensional stability of the poultry litter is not critical. If, however, this material were used in, for example, a cat litter product, which is available for household use, the dried effluent coating would be tracked by the animal throughout the household area.
U.S. Pat. No. 4,157,696 to Carlberg relates to an animal litter composition and method for making same in which mill effluent waste was combined with a coal fly ash composition. Although the products of U.S. Pat. No. 4,157,696 are said to rapidly absorb and deodorize animal waste liquid, the odor adsorbing capabilities and, in some cases, the liquid absorbency, of the U.S. Pat. No. 4,157,696 pellets do not meet the criteria for those properties, as hereinafter described.